Greywater Research Articles

Greywater treatment by zero-valent iron-modified sand filters: Performance and modelling using artificial neural network

Greywater treatment by zero-valent iron-modified sand filters: Performance and modelling using artificial neural network

Review on Membrane Biofouling Occurring in MBR and Its Related Technologies for Greywater or Wastewater Treatment

Scarcity of water resource recommended developing innovative technology to reclaim wastewater. Greywater is an appropriate source to reuse through advanced treatment. Meanwhile, MBRs are novel techniques to reclaim wastewater, which are composed of activated sludge processes and membrane filtration. Characteristic and application of Hybrid MBR, MBMBR and OMBR were reviewed in this article. And sources, analysis methods and controlling methods of biofouling resulted from extracellular polymeric substances and soluble microbial products were also discussed. According to a detailed analysis of research publications, MBRs are promising techniques to reclaim wastewater.

Factors Affecting Farmers’ Perception of Greywater Irrigation in Urban Agriculture in the Colombo District, Sri Lanka

Factors Affecting Farmers’ Perception of Greywater Irrigation in Urban Agriculture in the Colombo District, Sri Lanka

Waterbirds in the Wetlands of Casiguran, Aurora, Philippines

The wetlands of Casiguran, Aurora, Philippines are primarily the source of livelihood for most of the coastal communities of the area. However, this also serves as a feeding ground for many of the migratory and resident waterbirds. There are waterbird species occurring in the area that need protection but only a few studies of these species exist. This study was conducted from February to March 2019 to census and identify the water birds present in the study site, determine the conservation status and index of abundance of identified waterbirds, and describe their habitat association. Based on the result, 18 waterbird species in five families were present in the area. Family Ardeidae had six representative species, Family Charadriidae had five representative species, Family Scolopacidae had five representative species while only one species represents the Family Anatidae and Family Rallidae. Two waterbird species observed (Anas luzonica and Egretta eulophotes) were listed by the International Union for Conservation of Nature (IUCN) as vulnerable and another species (Numerius madagascariensis) was listed as endangered. In terms of abundance, Intermediate Egret (Egretta intermedia) was revealed as the most abundant (94.68%) among waterbirds. Different waterbird species prefer specific habitats. Some usually frequent freshwater and saltwater habitats, including mangroves, open sea, and watercourses inside forests while some were observed in mudflats, and rice fields during the survey.

A Cradle-to-Cradle Novel Approach for Wastewater Management in Sustainable Urban Communities

Water, a valuable resource to human lives, is being abused and driven to scarcity. This scarcity is leading some countries and areas to face difficulty in accessing drinking water. As the UN recently stated “by 2050 water shortages and harder access will be reached by around 2/3rd of the world total population” [1], thus, there is a high need to treat and reuse wastewater for domestic purposes, which will lead to less reliance on fresh water as an initial water source. Greywater—defined as the water produced in domestic houses including sinks and bathroom showers, and excluding any blackwater mix which is collected from toilets—is a type of wastewater. Greywater accounts for up to 75% of the daily water produced [2] while it has fewer contaminants when compared to blackwater. This makes greywater a focal point for treatment, and reusing to conserve fresh water and approach net zero water concept. Even though the definition of greywater is the same globally, its criteria can differ from one country to another, from one building to another, or even from the same person’s usage along the day. Accordingly, several treatment methods evolved over years aiming at treating the produced greywater for reuse mainly in irrigation and toilet flushing. The objective of this paper is to demonstrate a novel net zero wastewater approach applying cradle-to-cradle concept for urban communities; while also proposing a sustainable greywater treatment technique that is environmentally friendly, cost-effective and socially acceptable.

Effect of different types of fillers in membrane bioreactors for greywater treatment and membrane fouling

Effect of different types of fillers in membrane bioreactors for greywater treatment and membrane fouling

Variant analysis of financial and energy efficiency of the heat recovery system and domestic hot water preparation for a single-family building: The case of Poland

Significant amounts of waste heat are deposited in wastewater, which can be used e.g. for heating domestic water. The aim of the paper was to analyze the efficiency of energy recovery from gray water using a new horizontal heat exchanger in the form of a linear drainage equipped with a wavy middle wall. The experimental research consisted of the analysis of efficiency of the device prototype, and then the calculation of energy savings for the preparation of domestic hot water for 81 test cases. Installations cooperating with an electric and gas water heater were analyzed. A Life Cycle Cost analysis was carried out for the financial effectiveness of a conventional installation and an installation equipped with a heat exchanger for a family of 3. Research have shown that the new heat exchanger reduces energy consumption for hot water preparation by an average of 22–31%. It was established that when using an electric water heater, the investment costs pay back in the period of 4–9 years, and in the case of a gas heater, at least 12 years. The sensitivity analysis showed that an increase in energy prices can significantly shorten the payback period, to 6 years for a gas heater and 2 years for an electric heater. Research has shown that the new heat exchanger can significantly reduce the amount of energy needed to prepare domestic hot water. The research results can be useful for researchers, designers and potential users of heat recovery systems.

Effects of domestication on responses of chickens and red junglefowl to conspecific calls: A pilot study.

Beyond physical and zootechnical characteristics, the process of animal domestication has also altered how domesticated individuals, compared to their wild counterparts, perceive, process, and interact with their environment. Little is known, however, on whether and how domestication altered the perception of conspecific calls on both domesticated and wild breeds. In the present work, we compared the vigilance behavior of domestic and captive-born wild fowl following the playback of chicken alarm calls and contentment calls (control). The playback tests were performed on four different breeds/lines. We first compared the behavioral reaction of domesticated White Leghorn (WL, a breed selected for egg production) and Red Junglefowl (RJF) hens (ancestor of domestic chickens). We also compared the behavior of Red Junglefowl hens selected for high or low fear of humans (RJF HF and RJF LF, respectively), a proxy to investigate early effects of domestication. Contrary to our expectations, no breed/line reacted accordingly to the calls, as the increase in vigilance behavior after the playback calls was similar for both alarm and contentment calls. Although no call discrimination differences were found, breeds did differ on how they reacted/habituated to the calls. Overall, WL were more vigilant than RJF, and birds from the RJF LF line decreased their vigilance over testing days, while this was not the case for the RJF HF line. These results suggest that birds under commercial-like conditions are unable to discriminate between alarm and contentment calls. Interestingly, domestication and selection for low fear of humans may have altered how birds react to vocal stimuli. It is important to consider that farmed animals may interpret and be affected by the vocalizations of their conspecifics in unexpected ways, which warrants further investigation.

Reduction of pathogens in greywater with biological and sustainable treatments selected through a multicriteria approach.

Non-potable reuse of greywater (GW) can represent a valid alternative to freshwater consumption, satisfying the Sustainable Development Goals promoted by United Nations. The Multi-Criteria Analysis (MCA) was applied to select the most suitable processes for the reduction of microbiological contamination in GW. A pilot plant, including horizontal flow constructed wetland (CW) and anaerobic filtration (AF) in parallel, best treatment options according to MCA results, was built to treat GW collected from a Venezuelan family. (i) The removal efficiency of microbiological parameters, and (ii) the turbidity as possible microbiological contamination indicator and possible influence factor of disinfection treatment, were investigated. Except for Escherichia coli (4.1 ± 0.9 log reduction with AF), CW achieved the best reductions yields for total coliforms, faecal coliforms, and Salmonella, respectively equal to 3.1 ± 0.5 log, 4.3 ± 0.5 log, and 2.9 ± 0.4 log. In accordance with Venezuelan legislation and WHO guidelines, GW treated with CW was found to be suitable for irrigation reuse for non-edible crops. However, the reduction of pathogens by CW should be considered as a preliminary and not complete disinfection treatment. To reuse GW, especially in the irrigation of edible crops, stronger disinfection treatment should be considered as a complement to the preliminary disinfection performed by CW, to avoid any kind of risk. No significant correlation was found for turbidity either as a possible predictor of microbiological contamination or as an influence on biological disinfection.

Water footprint and wastewater quality assessment of yeast single cell oil production: Gate to gate approach for industrial water sustainability

Effective water resource utilization and sustainability for industrial operations is a growing concern. With increased industrial water demand, abstraction and water quality changes are rising. In India, distilleries generate more than 40.4 billion litres of effluent daily within the fermentation industry. Water, a public good with market and opportunity costs, needs effective mapping and management. Emerging distillery processes such as yeast lipid fermentation, if developed along with water sustainability, could aid in advancing water resource management. In the scope of this idea, the present study focuses on assessing the water footprint and water quality mapping for Rhodotorula mucilaginosa IIPL32 lipid production using crude glycerol, a by-product of the biodiesel industry. The assessment was based on primary data generated during the 500 L plant scale operation. The process's blue water footprint was assessed by applying a chain-summation approach, and the grey water requirement was determined by measuring water quality parameters for the effluent streams. The process's net blue and grey water footprint were estimated to be 3.87 and 23.66 m3 water/kg of lipid, respectively. Water quality index ratings were identified for all the respective water streams within the processing system, and human risk factors were estimated. The results suggested proper treatment of the spent broth, whereas the secondary effluent stream from cleaning operations could be reutilized within the system. Quality mapping also suggested that the effluent's high organic and mineral load can be processed for water and material recovery, which may significantly reduce the process's grey water and pollution load.

Chromosome-level genome assembly of goose provides insight into the adaptation and growth of local goose breeds.

Anatidae contains numerous waterfowl species with great economic value, but the genetic diversity basis remains insufficiently investigated. Here, we report a chromosome-level genome assembly of Lion-head goose (Anser cygnoides), a native breed in South China, through the combination of PacBio, Bionano, and Hi-C technologies. The assembly had a total genome size of 1.19 Gb, consisting of 1,859 contigs with an N50 length of 20.59 Mb, generating 40 pseudochromosomes, representing 97.27% of the assembled genome, and identifying 21,208 protein-coding genes. Comparative genomic analysis revealed that geese and ducks diverged approximately 28.42 million years ago, and geese have undergone massive gene family expansion and contraction. To identify genetic markers associated with body weight in different geese breeds, including Wuzong goose, Huangzong goose, Magang goose, and Lion-head goose, a genome-wide association study was performed, yielding an average of 1,520.6 Mb of raw data that detected 44,858 single-mucleotide polymorphisms (SNPs). Genome-wide association study showed that 6 SNPs were significantly associated with body weight and 25 were potentially associated. The significantly associated SNPs were annotated as LDLRAD4, GPR180, and OR, enriching in growth factor receptor regulation pathways. We present the first chromosome-level assembly of the Lion-head goose genome, which will expand the genomic resources of the Anatidae family, providing a basis for adaptation and evolution. Candidate genes significantly associated with different goose breeds may serve to understand the underlying mechanisms of weight differences.

Comprehensive Analysis of the State of Technology in the Field of Waste Heat Recovery from Grey Water

The use of energy from waste can be a key means of reducing the consumption of fossil fuels and thus reduction of greenhouse gas emissions. Waste energy can be a worthy alternative to conventional energy sources in construction. This paper presents data on energy consumption for the preparation of domestic hot water in residential buildings. A review of the literature sources and inventions in the area of waste energy recovery from grey water was carried out. It also presents the results of research on prototypes of devices used to receive energy deposited in wastewater, published in recent years. The benefits of using drain water heat recovery systems for preheating utility water in residential buildings are presented. An analysis of technical solutions for grey water energy collection units was made, revealing their advantages and disadvantages. Great importance was attached to the review of patent sources as well as devices available on the market. According to the authors, the results of the technical review may be useful for contractors and designers of heat recovery equipment and installations, researchers and potential users of these technologies.

Water footprint of small-scale dairy farms in the central coast of Peru.

Worldwide, dairy sector consumes 19% of the water in the livestock sector. However, in Latin America, the amount of water used in this sector is unknown, especially in arid zones. On the other hand, water footprint (WF) is a methodology to estimate the use of water to produce a product. The aim of this work was to estimate the WF of dairy production in the arid zone of the Peruvian central coast. Data from five dairy farms were used. The WF was calculated in its three dimensions: green water, blue water and grey water. In addition, the WF was measured for categories: feed, drinking and service. To measure the WF of feed production, the CROPWAT software was used, whilst the NRC (2001) equations were used to estimate the drinking water. The reference unit was cubic metres per kilogram of fat and protein corrected milk (FPCM). In average, 99% of the WF comes from feed production, followed by drinking water (0.4%). From the three dimensions of the WF, green water is responsible of 60% of the WF, followed by the blue water (30%). Imported water represented 63% of the WF. In general, WF of dairy production in these systems was 0.66 m3/kg FPCM. In conclusion, feed production, as the main source of WF from which most is imported, shows the possibility of reducing the WF of these systems by prioritizing and optimizing water consumption by crops using local resources with lower water requirements.

Analysis of the Water Footprint of Central and Eastern Europe Countries

The article presents an analysis of the water footprint of five Central and Eastern European countries, i.e. Poland, Slovakia, Lithuania, Ukraine and Belarus. The first three are members of the European Union, the other two are not. These countries also differ in terms of climate. The green, blue and grey water footprints of crop production, grazing, animal water supply, industrial production and domestic water supply are analysed. The per capita water footprint is also calculated. It is the highest for the countries of the former Soviet Union, that is Ukraine, Belarus and Lithuania, and half as low for Poland and Slovakia. In the case of virtual water, Poland dominates in the area of import, and Ukraine in export. The index of the net import of virtual water is unfavourable for Ukraine and Lithuania and is much more positive for Poland and Belarus. When calculated per capita, the net import of green virtual water is the highest for Belarus (340 m3/person/year) and Poland (148 m3/person/year). A positive value of this index was also recorded for Slovakia and negative for Lithuania and Ukraine (-282 m3/person/year). Taking into account the exposure of the southern Ukraine steppe to water stress, this is not a favourable situation for greater export of virtual water than its import.

Survival of bovine-associated serotypes of Salmonella enterica in bedding sand

Cattle persistently infected with bovine-adapted serotypes of Salmonella enterica are an important animal health and food safety issue. One possible mechanism by which infection is sustained in a dairy herd is by survival of Salmonella in sand used as bedding material. In this study we assessed the survival of 107 to 108 cfu bovine-associated serotypes of Salmonella enterica (sv. Cerro, Dublin, and Heidelberg) in sterile sand, recycled bedding sand, and gray water collected from a Wisconsin dairy farm. All 3 serotypes persisted at relatively high numbers (>106 cfu/g) for at least 28 d in sterile sand, with Salmonella sv. Dublin decreasing less than 1 log10 over 70 d. To our surprise, when low numbers of Salmonella sv. Dublin (103 cfu) were inoculated into sterile sand, the organism multiplied within 3 d to approximately 106 cfu/g sand and persisted at that level for 28 d. When we inoculated Salmonella sv. Dublin into recycled bedding sand or sand taken directly from cow pens, we observed a significant decrease in colony-forming units by d 7. In contrast, we observed a significant increase in colony-forming units when Salmonella sv. Dublin was inoculated into gray water from the sand recycling system. These data demonstrate that Salmonella can persist for extended periods of time in bedding sand, although this is limited to some extent by the native microbiota in recycled bedding sand.

Low rents and low operating costs in social housing - an example from Germany

The social housing project “PassiveHouseSocialPlus” in Germany with 42 residential apartments demonstrates how low rents and low operating costs can be combined. Different concepts for reducing operating costs were implemented and tested in one refurbished and one new apartment building. High energy efficiency for heating (passive house standard) and domestic hot water preparationwere complemented by efficiency measures for household electricity (e.g. pre-installed energy-efficient kitchen appliances, LED lighting) and water savings through gray water usage for flushing toilets.Additionally, a flat rate billing scheme for most of the ancillary costs was established. Due to the overall low level of consumption, space heating and domestic hot water are also included in the flat rate with defined budgets. Displays in all apartments are informing the tenants about the used-up budget and show a forecast for the consumption of water and electricity until the end of the year.Results from more than two years of measuring are showing a low consumption of heat, which is about in the calculated range. The budgets for drinking water and electricity are slightly exceeded on average, nevertheless, the consumption levels are significantly below average consumption in Germany. The operating costs are around 30 % below the costs of comparable apartments in the same city.

The “Gravity” for global virtual water flows: From quantity and quality perspectives

The virtual water trade (VWT) has been proposed as a means of balancing national water budgets while also saving water globally. Since humans require both sufficient quantity and quality of water, the drivers of VWT flows should be thoroughly examined, including its three components. Multiregional input–output (MRIO) and gravity methods are used to investigate the influence of multiple factors on the green, blue, and grey water trading flows among 177 countries in 2014. Several factors were found to be strongly correlated with the grey water trade, offering valuable insight into water resource management, especially about water pollution. The findings verify the driving effects of socio-economic status and agricultural activities on virtual water trade. The study shows that the influence of water resources endowment on the virtual water trade flow is relatively small compared to economic structure in determining virtual water trade flows. The paper contributes to the research on the interaction between virtual water trade and various factors, which can assist decision-makers in optimizing economic structure by integrating water quantity and quality factors and realize sustainable management of water resources.

Assessment of water footprint for a few major crops in Banas River Basin of Rajasthan

Water security is essential for socio-economic development, ecosystem management, and environmental sustainability. An improved understanding of the relationships between water demand and supply is needed to mitigate the impacts of diminishing water resources. The present study aimed to assess the crop water footprint of sixteen major crops in the basin namely, bajra/ pearl millet (Pennisetum glaucum L.), barley (Hordeum vulgare L.), cotton (Gossypium herbaceum L.), gram/chickpea (Cicer arietinum L.), groundnut (Arachis hypogaea L.), guar/cluster beans (Cyamopsis tetragonoloba L.), jowar/ sorghum (Sorghum bicolor L.), lentil/ masoor (Lens culinaris L.), maize (Zea mays L.), mungbean (Vigna radiata L.), rapeseed & mustard (Brassica napus L.), rice/paddy (Oryza sativa L.), sesame (Sesamum indicum L.), soybean (Glycine max L.), urad/ black gram (Vigna mungo L.) and wheat (Triticum aestivum L.) was estimated during 2008-2020 in the Banas river basin of Rajasthan. The average annual water footprint of crop production varied from 11365.8-23131.5 MCM/yr (Mean 19254.5 MCM/yr) during the study period. Wheat, bajra, maize, rapeseed & mustard make up 67.4 % of the total average annual water footprint of crop production. The blue water footprint of crop production was 3942.1 MCM/yr, with wheat, rapeseed & mustard accounting for almost 87.0 % of the average annual blue water footprint. Blue, green and grey water footprints comprised 20.8, 69.7 and 9.5 % of the total WF of crop production in the basin, respectively. This assessment can play a significant role in developing better policies for properly managing water footprints for sustainable crop production in the basin.

Effects of advanced oxidation process on greywater treatment: an optimization study

Greywater is domestic wastewater from showers and sinks and has a significant potential for the protection of water resources as it is less polluted in terms of nutrients, inorganic substances and hazardous organic substances. It is aimed to treat and reuse greywater in order to meet the rapidly increasing water demand. In this research, the treatment of greywater using the Fenton Process was studied. The efficiency of the Fenton Process was optimized using the Box-Behnken Statistical Design Software. As a result of this study, 97.88 % of Chemical Oxygen Demand removal was achieved at pH = 3, Fe 2+ dose of 3 mM, H2O2 dose of 2 mM, and 37 min. The effect of Potassium Permanganate on the treatability of synthetic greywater was also investigated in the study. Results showed that 84% of the Chemical Oxygen Demand removal efficiency could be achieved using 0.1 g/L Potassium Permanganate at the end of 1 hour reaction time.

A bibliometrics review of hotspots in water footprint research based on co-words network analysis

The uneven distribution of water resources and production fragmentation make the study of water footprint an important part of water resources management and environmental research. This paper provides a bibliometrics analysis of 3822 papers related to the water footprint topic before 2021, including 2381 English papers from the Science Citation Index (SCI) database and 1441 Chinese papers from the China National Knowledge Infrastructure (CNKI) database. We applied the method of co-word analysis to study the changes in hot research fields in four stages and represented a comparative analysis of highly cited papers and the application of water footprint theory in various sectors. First, water footprint can be divided into two categories: “volumetric” water footprint and “impact-oriented” water footprint. “Volumetric” water footprint methodology focuses on water consumption while “impact-oriented” water footprint methodology focuses more on the environmental impact of water use. Water scarcity, carbon footprint, and grey water are the high-frequency keywords of both two databases. The research linkage of papers related to water footprint from the SCI database has gradually shifted to climate change and carbon emission, while, those from the CNKI database are more closely linked to ecological footprint and sustainable development. Second, SCI’s highly cited papers prefer to study the water footprint through scientific experiments from a bottom-up perspective, while CNKI’s highly cited papers prefer to combine economics and management theories to study the water footprint from a top-down perspective. In addition, water footprint theory is mainly applied in agriculture and industrial sectors and less in service sectors. This paper provides a review of water footprint research on a large scale and a reference for future research on water footprint.